230 likes | 510 Views
Assisted reproductive technologies (ART). By Doaa Hegab. Range of techniques for manipulating oocytes and sperms to overcome infertility. Major groups:. A rtificial insemination husband (AIH). FASIAR (Follicle aspiration, sperm injection & assisted rupture).
E N D
Assisted reproductive technologies(ART) By Doaa Hegab
Range of techniques for manipulating oocytes and sperms to overcome infertility.
Major groups: • Artificial insemination husband (AIH). • FASIAR (Follicle aspiration, sperm injection & assisted rupture). • In vitro fertilization (IVF) & embryo transfer (ET). GIFT & ZIFT • Gametes micromanipulation (ICSI & IMSI).
Encompasses also: • Ex utero and in utero fetal surgery. • Cryopreservation & screening sperm and embryos. • Micromanipulating and cloning embryos.
Artificial insemination husband (AIH) • Process by which sperms are placed into the reproductive tract of a female for the purpose of impregnating her by using means other than sexual intercourse.
Indications: • Mechanical infertility. • Defective seminal parameters: -low count, motility or abnormal forms. -low or high volume, high viscosity or abnormal liquefaction. • Immune infertility. • Idiopathic infertility.
Preparation: • Ovulation induction & monitoring. • Semen processing: * Semen wash with sperm culture media & centrifugation. * Selection of motile sperms. * Stimulation of motile spers.
Techniques: • Intracervical insemination (ICI). ‘Unwashed' or raw semen may be used. Easy,semen is injected high into the cervix with a needle-less syringe. • Intrauterine insemination (IUI). Washed sperm' can be injected directly into a woman's uterus • Intratubal insemination (ITI). No beneficial effect compared with IUI. ITI however, should not be confused with gamete intrafallopian transfer, where both eggs and sperm are mixed outside the woman's body and then immediately inserted into the Fallopian tube where fertilization takes place. • Intraperitoneal insemination (IPI).Prepared semen is injected into Douglas pouch.
FASIAR • A transvaginal ultrasound-guided needle is used to puncture follicles in the ovary. • The follicular fluid is aspirated with oocyte into a syringe that also holds the semen. This mixture is then immediately injected back into the follicle. • Because the total injected volume is much greater than the volume of the original follicle, the fluid was noted to flow out of the follicle and into the peritoneal cavity. • Differs from GIFT in that it depends on the tubal fimbriae to pick up the oocytes. FASIAR may reduce the risk of multiple births and is less expensive than other procedures.
IVF & ET • A process by which oocyte is fertilised by prepared sperms outside the body (in vitro). • IVF is a major treatment in infertility when other methods of assisted reproductive technology have failed. • The process involves hormonally controlling the ovulatory process, removing ova from the woman's ovaries and letting sperm fertilise them in a fluid culture medium.
Ovarian stimulation Treatment cycles are typically started on the third day of menstruation and consist of a regimen of fertility medications to stimulate the of multiple follicles of the ovaries. In most patients injectable gonadotropins (usually FSH analogues) are used under close monitoring. Such monitoring frequently checks the estradiol level and, by means of gynecologic ultrasonography, follicular growth. Typically approximately 10 days of injections will be necessary. Spontaneous ovulation during the cycle is typically prevented by the use of GnRH agonists or GnRH antagonists, which block the natural surge of luteinising hormone (LH).
Egg retrieval Transvaginal oocyte retrieval • When follicular maturation is judged to be adequate, human chorionic gonadotropin (hCG) is given. This agent, which acts as an analogue of luteinising hormone, would cause ovulation about 42 hours after injection, but a retrieval procedure takes place just prior to that, in order to recover the egg cells from the ovary. The eggs are retrieved from the patient using a transvaginal technique involving an ultrasound-guided needle piercing the vaginal wall to reach the ovaries. Through this needle follicles can be aspirated, and the follicular fluid is handed to the IVF laboratory to identify ova. It is common to remove between ten and thirty eggs. The retrieval procedure takes about 20 minutes and is usually done under conscious sedation or general anesthesia.
Fertilisation In the laboratory, the identified eggs are stripped of surrounding cells and prepared for fertilisation. In the meantime, semen is prepared for fertilisation by removing inactive cells and seminal fluid. If semen is being provided by a sperm donor, it will usually have been prepared for treatment before being frozen and quarantined, and it will be thawed ready for use. The sperm and the egg are incubated together at a ratio of about 75,000:1 in the culture media for about 18 hours. In most cases, the egg will be fertilised by that time and the fertilised egg will show two pronuclei. • The fertilised egg is passed to a special growth medium and left for about 48 hours until the egg consists of six to eight cells.
Selection Laboratories have developed grading methods to judge oocyte and embryo quality. Typically, embryos that have reached the 6-8 cell stage are transferred three days after retrieval, however sometimes embryos are placed into an extended culture system with a transfer done at the blastocyst stage at around five days after retrieval, especially if many good-quality embryos are still available on day 3. Blastocyst stage transfers have been shown to result in higher pregnancy rates.
Embryo transfer Embryos are graded by the embryologist based on the number of cells, evenness of growth and degree of fragmentation. The number to be transferred depends on the number available, the age of the woman and other health and diagnostic factors. • The embryos judged to be the "best" are transferred to the patient's uterus through a thin, plastic catheter, which goes through her vagina and cervix. Several embryos may be passed into the uterus to improve chances of implantation and pregnancy.
The sperm and the egg are incubated together at a ratio of about 75,000:1 in the culture media for about 18 hours. In most cases, the egg will be fertilised by that time and the fertilised egg will show two pronuclei. The fertilised egg is passed to a special growth medium and left for about 48 hours until the egg consists of six to eight cells. • The fertilised egg (zygote) is then transferred to the patient's uterus with the intent to establish a successful pregnancy (ET).
Indications(as AIH) • Mechanical infertility. • Defective seminal parameters: -low count, motility or abnormal forms. -low or high volume, high viscosity or abnormal liquefaction. • Immune infertility. • Idiopathic infertility. • Irreversible tubal obstruction.
Complications • The major complication of IVF is the risk ofmultiple births. With increased risk of pregnancy loss, obstetrical complications, prematurity, and neonatal morbidity. • However recent evidence suggest that singleton offspring after IVF is at higher risk for lower birth weight for unknown reasons • Another risk of ovarian stimulation is the development ofovarian hyperstimulation syndrome. • If the underlying infertility is related to abnormalities in spermatogenesis, it the male offspring is at higher risk for sperm abnormalities. • Birth defects: certain birth defects could be significantly more common in infants conceived with IVF, notablyseptal heart defects, cleft lipwith or withoutcleft palate, esophageal atresia, andanorectal atresia; the mechanism of causality is unclear
Gamete intrafallopian transfer (GIFT) • The oocytes will be harvested after ovarian stimulation, mixed with the prepared sperms suspension, and placed back into the woman's Fallopian tubes during a single laparoscopy. • More simple, physiological & cheap than IVF. • Results not better than IVF.
Zygote intrafallopian transfer (ZIFT) • The oocytes will be harvested after ovarian stimulation by transvaginal ultrasound-guided ovum retrieval. Co- incubation with prepared semen & after fertilization in the laboratory the resulting early embryos or zygotes are placed into the fallopian tubes using a laparoscope. • However, the need for two interventions and the fact that IVF results are equal or better leaves few if any indications for this intervention.